From: dave.long@linaro.org (David Long)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v11 4/9] arm64: add conditional instruction simulation support
Date: Mon, 21 Mar 2016 04:35:13 -0400 [thread overview]
Message-ID: <56EFB241.80909@linaro.org> (raw)
In-Reply-To: <20160314073803.22c90d69@arm.com>
On 03/14/2016 03:38 AM, Marc Zyngier wrote:
> On Mon, 14 Mar 2016 09:34:55 +0530
> Pratyush Anand <panand@redhat.com> wrote:
>
> Hi Pratyush,
>
>> On 13/03/2016:12:09:03 PM, Marc Zyngier wrote:
>>> On Wed, 9 Mar 2016 00:32:18 -0500
>>> David Long <dave.long@linaro.org> wrote:
>>>
>>>> +pstate_check_t * const opcode_condition_checks[16] = {
>>>> + __check_eq, __check_ne, __check_cs, __check_cc,
>>>> + __check_mi, __check_pl, __check_vs, __check_vc,
>>>> + __check_hi, __check_ls, __check_ge, __check_lt,
>>>> + __check_gt, __check_le, __check_al, __check_al
>>>
>>> The very last entry seems wrong, or is at least the opposite of what
>>> the current code has. It should be something called __check_nv(), and
>>> always return false (condition code NEVER).
>>
>> May be __check_nv() name is more appropriate as per definition, but shouldn't it
>> still return true, because TRM says:
>> "The condition code NV exists only to provide a valid disassembly of the 0b1111
>> encoding, otherwise its behavior is identical to AL"
>
> Indeed, I missed that. But this interpretation is for the A64
> instruction set, and this array is also used by the new
> arm32_check_condition. The condition code table for A32 seems to
> completely ignore the 0b1111 code (there is simply no entry for it), and
> it is only in the ConditionHolds pseudocode that you can see how this
> is actually special-cased.
>
> So I'm fine leaving the code as it is, but a comment and a pointer to
> the ARMv8 ARM wouldn't go amiss.
>
> Thanks,
>
> M.
>
OK.
-dl
next prev parent reply other threads:[~2016-03-21 8:35 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 5:32 [PATCH v11 0/9] arm64: Add kernel probes (kprobes) support David Long
2016-03-09 5:32 ` [PATCH v11 1/9] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature David Long
2016-03-11 18:07 ` James Morse
2016-03-18 13:06 ` David Long
2016-03-15 11:04 ` Marc Zyngier
2016-03-21 7:08 ` David Long
2016-03-09 5:32 ` [PATCH v11 2/9] arm64: Add more test functions to insn.c David Long
2016-03-09 5:32 ` [PATCH v11 3/9] arm64: add copy_to/from_user to kprobes blacklist David Long
2016-03-15 18:47 ` James Morse
2016-03-16 5:43 ` Pratyush Anand
2016-03-16 10:27 ` James Morse
2016-03-17 7:57 ` Pratyush Anand
2016-03-18 13:29 ` Pratyush Anand
2016-03-18 14:02 ` James Morse
2016-03-18 14:43 ` Pratyush Anand
2016-03-18 18:12 ` James Morse
2016-03-21 5:17 ` Pratyush Anand
2016-03-21 14:52 ` Will Deacon
2016-03-22 16:51 ` Pratyush Anand
2016-03-17 12:04 ` 平松雅巳 / HIRAMATU，MASAMI
2016-03-09 5:32 ` [PATCH v11 4/9] arm64: add conditional instruction simulation support David Long
2016-03-13 12:09 ` Marc Zyngier
2016-03-14 4:04 ` Pratyush Anand
2016-03-14 7:38 ` Marc Zyngier
2016-03-21 8:35 ` David Long [this message]
2016-03-09 5:32 ` [PATCH v11 5/9] arm64: Kprobes with single stepping support David Long
2016-04-20 1:29 ` Li Bin
2016-03-09 5:32 ` [PATCH v11 6/9] arm64: kprobes instruction simulation support David Long
2016-03-12 3:56 ` Marc Zyngier
2016-03-21 9:39 ` David Long
2016-03-09 5:32 ` [PATCH v11 7/9] arm64: Add trampoline code for kretprobes David Long
2016-03-13 13:52 ` Marc Zyngier
2016-03-21 13:30 ` David Long
2016-03-09 5:32 ` [PATCH v11 8/9] arm64: Add kernel return probes support (kretprobes) David Long
2016-03-17 12:22 ` 平松雅巳 / HIRAMATU，MASAMI
2016-03-17 12:58 ` 平松雅巳 / HIRAMATU，MASAMI
2016-03-21 13:33 ` David Long
2016-03-09 5:32 ` [PATCH v11 9/9] kprobes: Add arm64 case in kprobe example module David Long
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